Snow flies self-amputate freezing limbs to sustain behavior at sub-zero temperatures.

Temperature profoundly impacts all living creatures. In spite of the thermodynamic constraints on biology, some animals have evolved to live and move in extremely cold environments. Here, we investigate behavioral mechanisms of cold tolerance in the snow fly (Chionea spp.

Biomechanical origins of proprioceptor feature selectivity and topographic maps in the Drosophila leg.

Our ability to sense and move our bodies relies on proprioceptors, sensory neurons that detect mechanical forces within the body. Different subtypes of proprioceptors detect different kinematic features, such as joint position, movement, and vibration, but the mechanisms that underlie proprioceptor feature selectivity remain poorly understood. Using single-nucleus RNA sequencing (RNA-seq), we found that proprioceptor subtypes in the Drosophila leg lack differential expression of mechanosensitive ion channels.

Synaptic architecture of leg and wing premotor control networks in .

Animal movement is controlled by motor neurons (MNs), which project out of the central nervous system to activate muscles. MN activity is coordinated by complex premotor networks that allow individual muscles to contribute to many different behaviors. Here, we use connectomics to analyze the wiring logic of premotor circuits controlling the leg and wing.

Comment on 'A conserved strategy for inducing appendage regeneration in moon jellyfish, , and mice'.

Abrams et al. report that a simple dietary supplement is sufficient to induce appendage regeneration in jellyfish, fruit flies, and mice (Abrams et al., 2021).

Imaginal disk growth factors are Drosophila chitinase-like proteins with roles in morphogenesis and CO2 response.

Chitinase-like proteins (CLPs) are members of the family 18 glycosyl hydrolases, which include chitinases and the enzymatically inactive CLPs. A mutation in the enzyme's catalytic site, conserved in vertebrates and invertebrates, allowed CLPs to evolve independently with functions that do not require chitinase activity. CLPs normally function during inflammatory responses, wound healing, and host defense, but when they persist at excessive levels at sites of chronic inflammation and in tissue-remodeling disorders, they correlate positively with disease progression and poor prognosis.

Functional architecture of neural circuits for leg proprioception in Drosophila.

To effectively control their bodies, animals rely on feedback from proprioceptive mechanosensory neurons. In the Drosophila leg, different proprioceptor subtypes monitor joint position, movement direction, and vibration. Here, we investigate how these diverse sensory signals are integrated by central proprioceptive circuits.

Reconstruction of motor control circuits in adult Drosophila using automated transmission electron microscopy.

To investigate circuit mechanisms underlying locomotor behavior, we used serial-section electron microscopy (EM) to acquire a synapse-resolution dataset containing the ventral nerve cord (VNC) of an adult female Drosophila melanogaster. To generate this dataset, we developed GridTape, a technology that combines automated serial-section collection with automated high-throughput transmission EM. Using this dataset, we studied neuronal networks that control leg and wing movements by reconstructing all 507 motor neurons that control the limbs.

Central processing of leg proprioception in .

Proprioception, the sense of self-movement and position, is mediated by mechanosensory neurons that detect diverse features of body kinematics. Although proprioceptive feedback is crucial for accurate motor control, little is known about how downstream circuits transform limb sensory information to guide motor output. Here we investigate neural circuits in that process proprioceptive information from the fly leg.

The Function and Organization of the Motor System Controlling Flight Maneuvers in Flies.

Animals face the daunting task of controlling their limbs using a small set of highly constrained actuators. This problem is particularly demanding for insects such as Drosophila, which must adjust wing motion for both quick voluntary maneuvers and slow compensatory reflexes using only a dozen pairs of muscles. To identify strategies by which animals execute precise actions using sparse motor networks, we imaged the activity of a complete ensemble of wing control muscles in intact, flying flies.

Sp1 modifies leg-to-wing transdetermination in Drosophila.

During Drosophila development, the transcription factor Sp1 is necessary for proper leg growth and also to repress wing development. Here we test the role of Sp1 during imaginal disc regeneration. Ubiquitous expression of wg induces a regeneration blastema in the dorsal aspect of the leg disc.

The three leg imaginal discs of Drosophila: "Vive la différence".

The imaginal discs of Drosophila are the larval primordia for the adult cuticular structures of the adult fly. Fate maps of different discs have been generated that show the localization of prospective adult structures. Even though the three legs differ in their morphology, only the fate map for the T1 (prothoracic) leg disc has been generated.

Drosophila twin spot clones reveal cell division dynamics in regenerating imaginal discs.

Cell proliferation is required for tissue regeneration, yet the dynamics of proliferation during regeneration are not well understood. Here we investigated the proliferation of eye and leg regeneration in fragments of Drosophila imaginal discs. Using twin spot clones, we followed the proliferation and fates of sister cells arising from the same mother cell in the regeneration blastema.

Regeneration and transdetermination: the role of wingless and its regulation.

Imaginal discs of Drosophila have the remarkable ability to regenerate. After fragmentation wound healing occurs, ectopic wg is induced and a blastema is formed. In some, but not all fragments, the blastema will replace missing structures and a few cells can become more plastic and transdetermine to structures of other discs.

The twin spot generator for differential Drosophila lineage analysis.

In Drosophila melanogaster, widely used mitotic recombination-based strategies generate mosaic flies with positive readout for only one daughter cell after division. To differentially label both daughter cells, we developed the twin spot generator (TSG) technique, which through mitotic recombination generates green and red twin spots that are detectable after the first cell division as single cells. We propose wide applications of TSG to lineage and genetic mosaic studies.

Three genes control the timing, the site and the size of blastema formation in Drosophila.

Regeneration is a vital process to maintain and repair tissues. Despite the importance of regeneration, the genes responsible for regenerative growth remain largely unknown. In Drosophila, imaginal disc regeneration can be induced either by fragmentation and in vivo culture or in situ by ubiquitous expression of wingless (wg/wnt1).

Regulation of cellular plasticity in Drosophila imaginal disc cells by the Polycomb group, trithorax group and lama genes.

Drosophila imaginal disc cells can switch fates by transdetermining from one determined state to another. We analyzed the expression profiles of cells induced by ectopic Wingless expression to transdetermine from leg to wing by dissecting transdetermined cells and hybridizing probes generated by linear RNA amplification to DNA microarrays. Changes in expression levels implicated a number of genes: lamina ancestor, CG12534 (a gene orthologous to mouse augmenter of liver regeneration), Notch pathway members, and the Polycomb and trithorax groups of chromatin regulators.

A transient cell cycle shift in Drosophila imaginal disc cells precedes multipotency.

When Drosophila imaginal discs regenerate, specific groups of cells can switch disc identity so that, for example, cells determined for leg identity switch to wing. Such switches in cell determination are known as transdetermination. We have developed a system by which individual cells are marked and monitored in vivo as they transdetermine so that their proliferation, cell sizes, and differentiation are accurately traced.